A tilt table test (TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the reflex syncope is manifested as either hypotension or bradycardia, while an orthostatic challenge is applied. The timing of the response to the orthostatic challenge, as well as the predominant component of the response help to differentiate between various forms of neurocardiogenic syncope, orthostatic hypotension and non-cardiovascular conditions (e.g., pseudosyncope). Medications, such as isoproterenol and nitrates, may increase TTT sensitivity. Sublingual nitrates are easiest to administer without the need of venous access. TTT can be combined with carotid sinus massage to evaluate carotid sinus hypersensitivity, which may not be present in supine position. TTT is not useful to access the response to treatment. Recently, implantable loop recorders (ILR) have been used to document cardioinhibitory reflex syncope, because pacemakers are beneficial in many of these patients, especially those over 45 years of age. The stepwise use of both TTT and ILR is a promising approach in these patients. Recently, TTT has been used for indications other than syncope, such as assessment of autonomic function in Parkinson's disease and its differentiation from multiple system atrophy.
Background Coronary artery disease (CAD) is the leading cause of diastolic dysfunction. Diastolic dysfunction is associated with adverse outcomes. Renal insufficiency is also associated with adverse outcomes in CAD patients. The interaction between diastolic dysfunction and renal insufficiency is not completely elucidated. Aims We evaluated the prognostic value of diastolic function assessed by echocardiography in patients with and without renal failure undergoing coronary angiography. Patients and methods An observational prospective study of 547 consecutive patients undergoing coronary angiography. The median follow up was 30 months. Significant diastolic dysfunction was defined as elevated LV filling pressure with e/e'>12. Renal insufficiency was defined as adjusted GFR<60 ml/min. One hundred seventy-nine patients (32.7%) had significant diastolic dysfunction and 259 (47.3%) had renal insufficiency. Patients were categorized into 4 groups according to the presence of both significant diastolic dysfunction and renal insufficiency (Table 1). Results Significant diastolic dysfunction and renal insufficiency had additive effect on mortality (Table 1). A significant association was observed between diastolic dysfunction and mortality in patients with and without renal insufficiency (p<0.0001 & p=0.005, respectively). The presence of either diastolic dysfunction or renal insufficiency was associated with mortality (Figure 1), with the combination of both leading to the highest mortality (p<0.0001). In Cox regression model which combined diastolic dysfunction, presence of AF, LVEF, obstructive coronary disease on angiography, presence of acute coronary syndrome and renal insufficiency, both elevated filling pressure and renal insufficiency were independently associated with higher mortality (HR 2.65, CI 1.65–4.24, p<0.001 and HR 2.92, CI 1.72–4.98, p<0.0001, respectively). Table 1. Patients divided into 4 groups according to the presence of the significant diastolic dysfunction and renal insufficiency Patients' group N (%) Mortality Normal LV filling pressure / Normal renal function 230 (42.0%) 4.8% Elevated LV filling pressure / Normal renal function 58 (10.6%) 15.5% Normal LV filling pressure / Renal insufficiency 138 (25.2%) 15.9% Elevated LV filling pressure / Renal insufficiency 121 (22.1%) 38.8% P<0.0001 in Pearson Chi-Square. Fugure 1 Conclusions In patients undergoing coronary angiography, significant diastolic dysfunction with elevated filling pressure is associated with mortality in patients both with and without renal insufficiency. Both significant diastolic dysfunction and renal insufficiency are independent predictors of mortality.
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